Pittsburghers know that the times are out of joint. Somehow they're expecting the prosperity to blow up in their faces.
Fortune Magazine, 1941

Tuesday, October 07, 2008

What stock is this chart for?

I should have left the labels off of this and asked if people thought it was a) a graph of the stock market this year or b) enrollment in the City of Pittsburgh School District.

The thing is it is a picture that may or may not speak for itself. If you read the storiestoday on the subject you basically hear a lot of people speculating when they don't need to. Is the plunge due to demographic shifts in the region? in the city of Pittsburgh? or movement of students into private, parochial or charter schools? Some things are harder to answer than others, but I am pretty sure the school district has enough data to answer some of those questions without resorting to pure speculation. Based on last years enrollment, how many students were expected to show up this coming year? and since they are paying for them they should know how many students have shown up in charter schools? And since they are responsible for transporting some of them, they also might know if more students have gone into private schools. In recent years, this is a recurrent story and each time I read it I see different hypotheses thrown out there for what is going on, it shouldn't be such a mystery.

Obligatory caveats.. The years in the chart represent the beginning of the school year each cycle. So 2007 is for the 2007-8 school year as reported. Data for 1987-2005 is from the National Center for Education Statistics Common Core Data while the 2006 and 2007 data is as reported in the stories today. As such, I am not quite sure the 2006/7 data is reporting the exact same "total enrollment" number I pulled from the CCD. If someone shows me it isn't, I'll update the graph, but I bet the story is the same no matter. This is the data:

the only real amazing thing about that graph is how stable it was through 2000 or later.. the City of Pittsburgh population has been declining continuously for 50+ years. Non-college student/non-elderly population has been declinign even faster. It's the trend I would focus on, year over year fluctuations are probably just differences in the size of various age cohorts as they age through years they would be enrolled.